Time evolution of a decaying 2D turbulent flow computed by DNS using a pseudo-spectral code at resolution 512²: perspective visualization where the values are displayed as elevation.

Marie Farge and Alexandre Azzalini, LMD, ENS, Paris

The wavelet analysis have been performed on the time evolution of vorticity field presented in the films 1 and 2, using the continuous wavelet transform with the Morlet complex-valued wavelet. We took the same vorticity field at one instant, expand it into wavelets and then visualize the modulus of the wavelet coefficients. The red contour corresponds a threshold separating coherent and incoherent modes.

Marie Farge and Alexandre Azzalini, LMD, ENS, Paris

The wavelet analysis have been performed on the time evolution of vorticity field presented in the films 1 and 2, using the continuous wavelet transform with the Morlet complex-valued wavelet. Visualization of the isosurface corresponding to the threshold separating the coherent and incoherent modes during the flow evolution. The fact that the interface remains connected is a good indication that the CVS (Coherent Vortex Simulation) method works.

Marie Farge and Alexandre Azzalini, LMD, ENS, Paris

The wavelet analysis have been performed on a vorticity field at one instant. We expanded it into wavelets and made partial reconstructions, going from coarse to fine scales, and then back to coarse scales.

Marie Farge and Alexandre Azzalini, LMD, ENS, Paris
and Jean-François Colonna, CMAP, Ecole Polytechnique